Hi,

I have a 2015 with 137,000 miles, and a few days ago I started noticing a shudder when accelerating, and today it has become worse. From the outside, it sounds like rattling. The shuddering stops when coasting, it is at its worst when accelerating from a stop but still happens when you speed up while already moving, up until around 40MPH where after that it is not really noticeable. Up until yesterday, it was just a consistent judder when accelerating, but today it has some worse judders where it almost feels like a slipping.

Here is a list of things I have checked:

• When outside of the car, I can hear it from both sides of the car.
• RPM seems consistent when it is juddering.
• I can also feel it though the pedal and steering wheel.
• When I put the car on jack stands, put the car in drive, and accelerate (wheels in the air) I do not hear/feel it.
• Transmission fluid is at the correct level (HFC-2, changed 10,000 miles ago), no metal shavings or burnt smell when I opened the fill plug to check the level.
• Oil was changed a couple of weeks ago, no issues following that until a couple of days ago.
• Fuel injectors were replaced under the extended warranty on them around a year ago.
• The drivers side CV axel is solid, no movement.
• The passenger side CV axel has slight in and out play, but no up/down or side to side play.
• With the car on the ground, I started it, put it in drive and while holding the brake, and revved the engine to try to test the engine mounts, I didn’t not hear the rattle (I know this is not a perfect test).
• It also happens in reverse.
• I have checked engine mounts, control arm bushings and the torque mount, nothing looks failed, ripped or has any excessive play.
• No codes when doing a full system scan with a BlueDriver.

I have a feeling it is something between the transmission and the wheels. Any ideas as to what I can check?

Thank you in advance.

 

There shouldn't be. The outboard joint uses a precision ball bearing design that shouldn't have any play - only pivoting movement. Does the outboard joint move with the shaft, or is the play between the shaft and joint?

 

From what you’ve described, you’ve already done most of the right checks, so this is a good diagnostic position.The fact that it doesn’t show up with the wheels in the air is a big clue. That usually points away from the transmission itself and more toward something that loads under weight — CV joints under torque, engine/trans mounts shifting under load, or even a lightly failing inner CV that only shows symptoms when the suspension is compressed.Passenger inner CV with slight in/out play is worth a closer look, even if there’s no obvious click yet. Inner joints can shudder hard under load before they show obvious looseness. Also don’t fully rule out a torque mount that “looks fine” but collapses under acceleration.